The present invention relates to the secure tracking of pharmaceutical tablets, including the tablets themselves and methods for marking and verifying such tablets.
Pharmaceuticals and cosmetics are high technology products which require very specialized material systems and production procedures, as well as very large investments in development and marketing. Because of public safety concerns, authorities place very stringent requirements on the verification and authenticity of such products. Companies therefore have to make huge investments in the tracking and tracing of these products to ensure authenticity. In addition, because these products usually are distributed globally and have relatively large profit margins, cosmetics manufacturers and pharmaceutical companies suffer from and/or are susceptible to suffering from enormous losses due to counterfeiting. This includes direct losses due to lost sales, and also indirect losses due to the need to police trademarks, in order to protect the company's reputation. These problems have been aggravated by opportunities for increased sales over the Internet, where everything from counterfeit Viagra to false glucose tests seems to be readily available, anywhere.
Track-and-trace features in the pharmaceutical market are typically applied to packages. For example, holograms, optically variable inks, fluorescent dyes, and other identification features are attached to the packages, e.g., by adhesive tags. Alternatively, such labels are laminated to the carton or are directly applied to the packages. The main drawback of such labels is that they are not an integral part of the product or the packaging and therefore do not provide 100% security. And because the tablets themselves are not marked, they can be easily separated from the package, potentially leading to the refilling of the package with false products. Direct verification of the tablet, and ensuring that the authentic tablet is in the correct package are therefore primary concerns. Such track-and-trace procedures for the packages do not eliminate these concerns.
Further, few approaches are known for secure labelling of the tablet itself. And each of these tablet labelling approaches suffers from various drawbacks.
For instance, techniques based on forgery-resistant signatures, such as DNA of known sequence (U.S. Pat. No. 5,451,505) or molecules with characteristic isotopic composition or micro-particles with characteristic colour layer sequence (U.S. Pat. No. 6,455,157 B1), are considered unsuitable for pharmaceutical tablets, because these signatures are administered simultaneously and require additional regulatory approval.
Techniques based on a hologram on edible products are known. WO 01/10464 describes the coating of an edible product with a thermo formable and thus embossable layer. The tablets as disclosed in this document comprise a core, a coating, and a microstructure at the surface of said coating. The diffractive microrelief is visible to the unaided eye and exposed to mechanical stress, like abrasion. The microreliefs as described in this '464 application are generally considered to be very sensitive and thus susceptible to providing false results in verification methods. Still another drawback is that the methods for implementing the diffractive relief structure in such tablets, as described in this '464 application, are not considered compatible with the existing tablet mass production processes.
WO2006/027688A1 describes an article, such as a tablet, having a visible diffractive microstructure on its surface or at an interface. Illuminated with white light, the tablet shows a rainbow colour effect similar to a hologram. The diffractive microstructure can provide an indication of authenticity of the tablet. Although suitable for verification purposes, this '688 application discloses a security element that is visible to the unaided eye. Also, a relatively large area of the tablet needs to be covered by the microstructure to obtain good results regarding visibility.
A number of optical detection devices useful for analysing three-dimensional structures are known. White light interferometers are state of the art, but operate rather slowly. Optical coherence tomography (OCT) is another known technique capable of visualising three dimensional patterns, even if they are located at an interface below the surface of an article. The depth that can be visualised in a material depends on the optical properties of the material. Presently, that depth can be up to a few millimeters. U.S. Pat. No. 6,469,489 describes an array sensor which is used for parallel optical low-coherence tomography (pOCT) which enables real-time 3D imaging for topographic pattern. It provides fast, three-dimensional and structural information with spatial resolution in the micrometer range. This '489 patent does not disclose secure tracking of tablets. A plurality of electrical detection circuits with parallel outputs can form a one-dimensional or two-dimensional array sensor for the coherent or heterodyne analogue detection of intensity modulated optical signals simultaneously for all pixels with a high dynamic range. The array sensor may be used, e.g., for optical 3D measurements, and especially in optical low-coherence tomography. It is known to use OCT for investigating the human skin, to control the quality of fast production processes (e.g., in die-bonding), in SMD pick-and-place systems, as well as in mechanical inspection systems. Variants of these detection techniques do not use interferometry, but time-modulated optical signals to provide accurate 3D measurements of objects. Such variants often use parallel processing of lock-in signals on a single chip to provide fast and accurate distance information to an object. One example is time-of-flight (TOF) or related methods, where infrared or visible light from a camera's internal lighting source is time modulated and reflected by objects in the scene. The light travels back to the camera, where the time of arrival is measured independently by each pixel on a sensor array or chip. In contrast to conventional cameras, such cameras provide a complete distance map of all objects in the field of view on a pixel-by-pixel basis.
Altogether, there exists a need for the secure marking of tablets with security and tracking information, where the marking does not change the composition or the production process of the tablet, and can be easily read. There is also a need to link the marking information on the tablet to the package of the tablet, to reduce false delivery. Further, there is a need for a verification method that is contactless, fast, and reliable.